SQL >>VIEWS:

What is a view ?

A view is a virtual table based on the result-set of an SQL statement.

A view contains rows and columns, just like a real table. View contains only a single query.

purpose of views is to centralize the code and so that reusability of code will be there.

VIEW SYNTAX:

CREATE VIEW <VIEW NAME>

AS

?<QUERY>

GO

--READ THE DATA FROM A VIEW

SELECT *FROM <VIEW NAME>

--DROP A VIEW

DROP VIEW <VIEW NAME>

--SEE THE CODE

SP_HELPTEXT 'VIEW NAME'

--GET ALL THE VIEW NAMES

SELECT *FROM SYS.VIEWS

--CALL THE VIEW

SELECT *FROM VW_GETCUSTOMERS_BR1

NOTE:-VIEW CANNOT TAKE A INSERT/UPDATE/DELETE STATEMENTS

TYPES OF VIEWS

--UPDATEABLE VIEWS(READ/WRITE):

-SAME NO OF COLUMNS TO BE THERE IN TABLE AND VIEWS ,OTHERWISE REMAINING COLUMNS IN THE BASE TABLE MUST ALLOW NULL VALUES

-NO AGGREGATE FUNCTIONS , HAVING CLAUSES RTC

--NON UPDATABLE VIEWS(READ ONLY):

-CONTAINS AGGREGATE FUNCTIONS

-LESS NO OF COLUMNS THAN THE BASE TABLE ETC.